It is well known that charged particles are more readily captured by a filter media than are neutral particles. One of the most common ionizing air filters is a precipitator type air filter, which is an electronic air filter having ionizing wires of about 0.005 inches diameter, charged at about 7 Kilovolts, placed between grounded plates to generate a corona and charge the dust particles passing therethrough. Further down the airflow path, alternating charged and grounded plates collect the charged particles of dust. The disadvantage of precipitator type filters is that they are difficult to maintain, requiring regular cleaning of the collector plates, which get loaded with fine dust. Cleaning often requires using very strong detergents. Another disadvantage of the precipitator type filter is that they produce a significant amount of ozone. This occurs because the charging wires are placed near grounded surfaces. This arrangement generates corona all along the length of the wires, which can be seen glowing in the dark. Moreover, in some liquid filtration applications, such as filtrating of hydraulic fluid, a static charge can build up on the surface of the filter, potentially causing an explosion or fire hazard.
Accordingly, there remains a need for filter media having improved conductivity to enhance filtration efficiency and/or static electricity dissipation, and to methods for making the same.